1. Speed and Jump are fixed except for weight, then you run faster.
2. There is no spellmaking.
3. Some skills have more perks to them than others. Block for example only had about 8 or 9. Where as I think One-handed had a few more. It varies.
I like the above so I'll use it as my base answer, but to expand...
1. What ArcanePulse said and also, I speculate that higher stamina will allow you to sprint for longer periods of time, since sprinting (from what I've seen in some demo vids) depletes stamina.
2. No more spell making but you can duel cast the same spell for a powered up version of the spell.
2a. I am speculating that there is the possibility of combining two different spells (for certain configurations, not all would work). I say this because I created an account here around the announcement of Skyrim and at that time Todd was saying something like they were working with doing different variations of spell combos but it still wasn't working the way they wanted it to. They were experimenting. He wasn't sure if it was going to make it into the final game. That was then and this is now, and they wouldn't want to tell us every single detail about the magic system, so who knows what they've been able to get working with regards to combining spells.
2b. I am also speculating that you'll be able to add a temporary enchantment to your one-handed weapon when you have a weapon equipped in one hand and an spell in the other (again only for certain configurations), by pulling both triggers together (unless someone else can confirm what having the same configuration equipped does when you pull both triggers).
3. Since we haven't been shown all perk trees, there is still the possibility of having miscellaneous perks relating to extra boosts for Health, Magicka, Stamina, Jumping and Sprinting. Again, speculation.
So, for my speculating, I have no proof (hence it being speculation), it's just some things I've been thinking about. If it is in the game, you can PM me a cookie and if not, you can PM me that I had an ID-10-T error